A thermal recording material including a thermal recording layer formed on a support such as paper and a plastic film is widely used for, for example, output sheets for facsimiles, industrial measurement terminals, medical terminals, handy terminals, POS systems, and ticket dispenser systems. In a thermal recording material, in order protect the thermal recording layer from, for example, water, plasticizers, oils and fats, and solvents, a protection layer is formed on a thermal recording layer.
Patent Document 1 below has examined, as a material used for such a protection layer, an emulsion of a copolymer resin composed of a vinyl monomer component having a carboxyl group and a vinyl monomer that is copolymerizable with that.